The present invention relates generally to door trim panels. More specifically, the present invention relates to door trim panels having an armrest support component.
Conventional construction of automotive door trim panels employs many processes, constructions and materials to incorporate an armrest support component into the trim function. The purpose of this support component is to serve as a resilient surface which is comfortable to the occupant""s elbow and forearm. Many base level trim panels do not incorporate this feature due to cost restrictions, but rather opt for more economical solutions resulting in uncomfortable hard molded surfaces. Current process options needed to provide a separate soft armrest feature into the trim panel include the manufacturing of separate multi-layer structures consisting of substrates, soft interlayers and a coverstock which is molded into a composite in a final foaming mold. These manufacturing processes include rotational molding, blow molding, overshoot injection molding, foam-in-place (FIP) polyurethane molding and others. Additionally, the tools, equipment, and materials needed to manufacture these components are expensive and add substantial cost to the trim panel system.
Additionally, recent trends in trim design have been concentrated on weight reduction and improved crashworthiness. Current materials and structures associated with the armrest component are generally mass intensive and introduce a material structure which transfers impact loads directly to the occupant along with the added complication of fractured remnants of substrate materials being driven into the interior space. Design trends tend toward the aesthetic flow of like surfaces from the instrument panel through the door trim and into the rear cabin area. In the past, separate armrests introduced materials and surfaces which were more difficult to blend into acceptable levels of appearance. It would be beneficial to have a trim design that accommodates an appropriate harmony of color, gloss and texture.
The prior art teaches various designs. For example, U.S. Pat. No. 5,474,841 (Matsuki et al.) is directed to a cellular molded article of a polypropylene resin having a skin produced by placing a skin material on the surface of a die, clamping the die to form a mold, then charging the mold with pre-expanded particles of polyethylene resin, pre-heating the pre-expanded particles using steam supplied through the vapor holes of the die at a temperature lower than temperature at which the pre-expanded particles are melt bonded together, and then holding the pre-expanded particles in the steam. Next, main heating of the pre-expanded particles is applied through the die at a temperature not less than the temperature at which the pre-expanded particles are melt bonded together. At the time of the main heating of the pre-expanded particles through the die, the die may also be heated up as needed.
U.S. Pat. No. 5,928,734 (Scherf) is directed to a soft trim part which is suitable for an automobile interior dashboard or armrest. The trim part includes a core made of expanded polypropylene (EPP) to which a decorative layer (made of fabric and/or foil) is fused. To manufacture such a trim part, an edge zone of the EPP core is heated above a melting temperature and the decorative layer is applied and pressed on, fusing the decorative layer to the EPP core part. The fused area cools to form a skin-like carrier layer which is relatively stiff and solid, holding the decorative layer to the core part.
Many materials, methods, and designs are currently in use on vehicles to facilitate the resilient armrest feature on door trim panels. Performance and cost penalties are associated with these current solutions. Among these are high mass, high cost and the lack of energy absorbing characteristics. The separate soft armrest feature is, in many cases, the single most costly component in the trim system. The present invention offers an inexpensive alternative to those products. Economies are gained through the integration of the soft armrest into the surrounding bolster/trim panel. The invention encompasses a single step molding process thereby eliminating costs of many separate manufacturing operations such as molding substrate, forming covers, and finally insert molding the composite to form an armrest assembly.
All references cited herein are incorporated herein by reference in their entireties.
A process for manufacturing a door trim panel with an integral soft armrest pad is provided. First, a male steam chest mold half and a female steam chest mold half are provided. A cover material is loaded and restrained on the female mold half. The male mold half is closed relative to the female mold half to a fill position wherein a mold cavity is formed. At least one divider device is inserted into the mold cavity to separate the mold cavity into at least one low density volume and at least one high density volume. The high density volume of the mold cavity is filled with a quantity of a first polymeric material and the low density volume of the mold cavity is filled with a quantity of a second polymeric material (independently of the filling of the high density area). The divider device(s) are withdrawn from the mold cavity. The first and second polymeric materials are heated, using steam supplied through the vapor holes in the mold halves at a temperature not less than the temperature at which particles of each of the first and second polymeric materials are melt bonded together, including at positions where particles from the first polymeric material contact particles from the second polymeric material. The low density volume becomes the integral soft armrest pad at the completion of the process.
The step of filling the low density volume of the mold cavity with a second polymeric material may include, for example, filling the mold cavity with expanded polypropylene beads, expanded polyethylene beads, cross-linked polyethylene beads, or cross-linked polypropylene beads. The trim panel may also be molded with no material being injected into the cavity space defined by the divider devices. As a post molding process, the cavity may be filled with a polyurethane material or a material comprised of a polyolefin bead material which has been coated with adhesives.
The step of loading and restraining a cover material includes loading and restraining a cover material of a textile, for example, thermoplastic polyolefin, or a polyvinyl chloride. The cover material may have a backing material of, for example, cross-linked polypropylene, cross-linked polyethylene, polyurethane, thermoplastic polyolefin, or polypropylene. The cover material may cover less than the entire female mold half. The cover material may be pre-formed into a pre-defined shape or may be flat.
The step of loading and restraining a cover material onto the female mold half may include loading and restraining the cover material using mechanical devices, for example, pneumatic devices. The step of inserting at least one divider device may include inserting numerous devices, for example, retractable pins and blades mounted in the male mold half.
In an alternate embodiment of the present invention, a process for manufacturing a door trim panel with an integral soft armrest pad is provided which includes the steps of providing a male steam chest mold half and a female steam chest mold half, loading and restraining a cover material onto the female mold half, and closing the male mold half relative to the female mold half to a fill position wherein a mold cavity is formed. The process further includes the steps of inserting at least one divider device into the mold cavity to separate the mold cavity into at least one low density volume and at least one high density volume, filling the high density volume of the mold cavity with a quantity of a first polymeric material, and heating the first polymeric material using steam supplied through vapor holes in the mold halves at a temperature not less than the temperature at which particles of the first polymeric material are melt bonded together. Finally, the process further includes the steps of filling the low density volume of the mold cavity with a quantity of a second polymeric material, heating the second polymeric material using steam supplied through vapor holes in the mold halves at a temperature not less than the temperature at which particles of the second polymeric material are melt bonded together, and opening the male mold half relative to the female mold half and removing the finished door trim panel.
In another alternate embodiment of the present invention, a process for manufacturing a door trim panel with an integral soft armrest pad is provided which includes the steps of providing a male steam chest mold half and a female steam chest mold half, loading and restraining a cover material onto the female mold half, and closing the male mold half relative to the female mold half to a fill position wherein a mold cavity is formed. The process further includes the steps of inserting at least one divider device into the mold cavity to separate the mold cavity into at least one low density volume and at least one high density volume, filling the high density volume of the mold cavity with a quantity of a first polymeric material, and heating the first polymeric material using steam supplied through vapor holes in the mold halves at a temperature not less than the temperature at which particles of the first polymeric material are melt bonded together. Finally, the process includes the steps of opening the male mold half relative to the female mold half and removing the door trim panel, loading the door trim panel into a secondary mold and injecting or pouring a second polymeric material into an open cavity to form the soft armrest, heating the second polymeric material at a temperature sufficient to induce curing of the second polymeric material, and opening the male mold half relative to the female mold half and removing the finished door trim panel.
The step of heating the second polymeric material may include heating using heated water circulated through the male and female mold halves. The step of pouring the polymeric material may include pouring polyurethane. The step of pouring the polymeric material may include pouring a polyolefin bead material coated with an adhesive.
A door trim panel with an integral soft armrest pad is also provided which includes a panel having at least one section of a low density polymeric material and at least one section of a high density polymeric material. The section of the low density polymeric material is integral to the section of high density polymeric material. The section of low density polymeric material forms the soft armrest pad. The door trim panel further includes an integral cover material over at least a portion of the high density polymeric material. The cover material may be over at least a portion of the low density polymeric material also.
The section of the low density polymeric material may be, for example, expanded polypropylene beads, expanded polyethylene beads, cross-linked polyethylene beads, cross-linked polypropylene beads, or polyurethane. The cover material may be a textile of, for example, thermoplastic polyolefin or polyvinyl chloride. The cover material may have a backing material of, for example, cross-linked polypropylene, cross-linked, polyurethane, thermoplastic polyolefin, or polypropylene. The cover material may cover less than the entire female mold half. The cover material may be of a pre-formed shape or flat.